The subject for me with the budget at $20,000 is in the race car/motorcycle objects, moving, along with sports, working sometimes with low light. Nature, birds, animals, also an interest. So, what I actually have is the D4 with 400mm f/2.8 and the TC-20EIII, TC-14EII and all of it performs in a manner beyond my wildest expectations.

I would note, however, for the most part, unless one is looking at images side by side, the $2500 category will produce the same images at 10% of the cost. And for those shooting D40's, a used 80-400 will also do what the $20,000 budget will do, but the "keeper" rate will be only about 20% of that which comes out of the D4.

I have and use the 600mm f/4 and D4 combo and would not trade it for any other possible options. i also have and use the 300mm f/4. My primary photography is wildlife photography but I also photograph a variety of sporting events....especially equestrian events such as horse racing.

So....If I had this spare cash "laying around", I'd go with the 300mm f/2.8 as the perfect compliment to the 600mm.

I want a 400 2.8 to go with my D3s. I already have a TC14E II and TC20E III.

With the TC14E option I'd have almost a 600f4 or 560f4 I'd bet it as sharp also then with the TC20E I'd have a 800 5.6 in a pinch. I've used the TC14E with my AFS 300f4 with amazing results as a 560f4 I'd expect similar.

Plus the fact that the AF would be able to focus with more light when used as a 400f2.8.

@ Juergen...Well, this is a good question re: 600mm f/4.0. If I were to have only one lens...for me this is too long. And, "one lens" was sort of a limitation albeit one I altered somewhat. I think I chose the 400mm f/2.8 because of the ability to add the 2X and get out 800mm or on the new D400 it will be 1200mm effective (or D800 cropped at DX). I wanted the extra f/stop.

My current budget, while nice is not unlimited at present. But, if it were, I might do this:
D4 w/ 300mm f/2.8
D4 w/ 600mm f/4.0
or D4 w/ 200-400mm f/4 when shooting sporting events such as track and field.
A problem is, the 70-200f/2.8 w/ TC-20EIII is so good, and lighter than the 200-400mm f/4.0, it may be the track and field lens of choice. But, my copy of the 80-400mm f/4.5-5.6 is also very sharp....so...

And, one thing to point out, at my age, I place the 400mm on a very stout carbon tripod good for about 18 kg., with a Manfrotto gimbal head. Thus, I do not have to "hold it up" all the time and the risk of it falling over is minimal. Much more relaxing for me when $15,000 is sitting on the tripod....

In thinking about all this and the fact the D4 can AF at f/8, the 600mm f/4.0, TC-20EIII, yes...1200mm and with the potential for a crop sensor capable of AF at f/8, yikes, 1600mm effective..... But, it has been my experience, photographing with 800mm on FX and the subject is moving, requires a lot of skill. And even more luck. Sometimes I cannot even find the subject in the camera frame....as in flying birds... So at 1200mm or 1600mm, this I cannot imagine. But, if the economy really gets good, maybe a second body like a D800E, and....

Instead of the 600mm, why not go for the 500mm? You can use the 500 easily without a tripod, whereas the 600mm (or 400) isn't very handhold-able :p. You could always crop some. I handhold my 500mm all the time and get great shots, and I'm still using a D300 and not a FX ISO champ.

Definitely a 400 2.8 for me. It's the only lens still on my 'wish list', except maybe a PCE. Why the 400? Well I know it predictable, but you can turn a 400 2.8 into a 500 4, but not the other way round. Oh yes, and the fact that I have a thing for fast glass.

I would say for wildlife - bigger animals as I'm not a birder:
- d800 + N200-400 and N600/4 - why? I really don't need the speed of d4/ds3, sure it's nice but not essentials, whereas the few additional pixels does allow for some creativity
if I were on budget (which I am :))
- d800 + N70-200/2.8 + TC1.4 or TC 2.0 and N300/4 + TC 1.4 or TC 2.0 - not a perfect combination but works - like this combo for it's portability, though the N300/4 is certainly for update due to lack of sharpness on d800 and poor tripod support.

Under those conditions, for use with my D700 I would get the N300mm F2.8G + TC20EIII. Why? Flexibility and weight. 300mm is great for portraits, but also good for environmental shots of wildlife (with or without TC) and it doesn't weight too much to lug it around for a few hours.

The D5000 and 300 F4...amazing combo so far. I plan to add the 1.4 TC at some point, but so far the 300 has given me enough reach in most cases...bokeh is amazing and it is quickly becoming my favorite. Plus for the price I don't think you can beat it.

I have to add that opinion on this can vary totally on budget obviously and use. Personally I would rather have my 300 F4 and 1.4 TC then either the 70-200 or 80-400 to shoot what I have my 300 F4 for. Plus the 300 F4 is half the price of 70-200 VRII.

PB PM said:
Under those conditions, for use with my D700 I would get the N300mm F2.8G + TC20EIII. Why? Flexibility and weight. 300mm is great for portraits, but also good for environmental shots of wildlife (with or without TC) and it doesn't weight too much to lug it around for a few hours.

This is exactly what I have, and I think I made a good choice. It also all works great on my d300s for birds.

The advantage the 300 has over the 400-600's is that it is still practical inside. This is a big point.

That said it is still heavy. I saw the patent for the smaller 300 f4 with VR and went, WOH, now that would come in handy. I would probably wait until it comes out if you're patient.

Now if I had the funds I would have gotten the 300 F2.8. But looking at it...it weighs twice as much, costs 3 times as much and the 300 F4 can minimum focus at half the distance. Unless I was shooting professionally I think I prefer the 300 F4 actually...that said without having shot the 300 F2.8 though :)

adamz said:
I would say for wildlife - bigger animals as I'm not a birder:
- d800 + N200-400 and N600/4 - why? I really don't need the speed of d4/ds3, sure it's nice but not essentials, whereas the few additional pixels does allow for some creativity
if I were on budget (which I am :))
- d800 + N70-200/2.8 + TC1.4 or TC 2.0 and N300/4 + TC 1.4 or TC 2.0 - not a perfect combination but works - like this combo for it's portability, though the N300/4 is certainly for update due to lack of sharpness on d800 and poor tripod support.

I haven't heard the 300 F4 not being sharp (reviews even say comparable to the F2.8) and my copy is super sharp...I would say comparable to my 105 F2.8. Do you mean in the corners or what? I know the tripod collar is a bust, but the stock one is still OK. I plan to replace mine soon.

tcole1983 - let me explain myself :) bare N300/4 is ok on d800 (excellent on d3s), but once You add TC the quality drops visibly - maybe that's my particular lens, maybe not. on d3s the combo with TC17 works like a charm, on d800 it's soapy even when stopped down to f8. TC14 works a little bit better, but still not as good as on d3s.

For outdoor sports, I'd say the 200-400 and a D4. The 200-400 allows for some latitude in distance to the subject as the point of interest shifts around the field.

For night and indoor sports, the D4 and 300 f/2.8.

For portraits and landscape the 300 and D800.

I'd like to have the 600 f/4 for wildlife.

If I were to have but one of the listed lenses, I think I might stick with the 200-400. While I think that the 200 f/2, 300 f/2.8 and 400 f/2.8 all have a bit more contrast and are slightly sharper at infinity, for my use the zoom range is incredibly helpful... There are many times when moving to improve the framing isn't possible, where with a little forethought the 200-400 is ideal.

I would really like to have the 600 for wildlife. For large mammals I'd pair it with a D800, for birds I'd go with the D4.

These decisions are really very difficult. And, every opinion is so valid. The fact is not many are going to go for the lenses over $3000. And, as I have demonstrated on NRF, the 70-200mm f/2.8 VRII, with either the TC-20EIII, or the TC-14EII is so very good when used at f/8 and still quite good at f/5.6 (wide open) the most bang for the buck might be the D800 and above combination.
And this is $6000 worth. But, it gives a range from 70-400mm. And in the short range 70-200mm) f/2.8, mid range (100m to 280mm) f/4.0, and the long (140-400mm f/5.6.

If economy is desired, I seem to be able to get excellent results from my copy of the 80-400mm f/4.5-5.6. Generally at f/9 or smaller f/11 maybe. This would get one down to less than $4500 if the 80-400 were used.

All the discussion now has me confused but may be very helpful. I am planning a bus tour next year along "Going to the Sun Road" in Glacier National Park and will carry two bodies, one for wildlife, one for landscapes. The D4 will no doubt have the 70-200 w/TC-20EIII. And the D800 or whatever, the 24mm f/3.5 PC Nikkor for landscapes. So, wake up Mike I am coming your way.... next year.